Electrocardiologic device for the assisted diagnosis of brugada syndrome or early repolarization syndrome

Abstract

Electrocardiologic device for assisted diagnosis, preferably for the diagnosis of Brugada syndrome or Early Repolarization syndrome. This device allows characterizing the ventricular repolarization wave of an ECG signal collected from a patient. Extracting out of the ECG signal, for each heart beat, an ST segment is constituted of a succession of samples of the ventricular repolarization wave, taken within a time window ([Q ON +80 ms, Q ON +140 ms]) of a predetermined duration spreading from a moment of window onset defined by a time offset applied to a predetermined temporal origin given by the moment (Q ON ) of appearance of the QRS complex, whose time position is determined on the ECG signal for each heart beat. Quantizing computes an elevation index compared to a predetermined reference level (BL), and analyzing over a succession of heart beats the persistence and/or variation of this elevation index.

We claim: 
     
       1. A device for an assisted electrocardiologic diagnosis comprising means for characterizing the ventricular repolarization wave of an ECG signal collected from a patient, said ECG signal having been preliminarily sampled and digitized, said device comprising:
 means for determining the time position of a moment of appearance of the QRS complex on said ECG signal for each heart beat; 
 extracting means for isolating out of the ECG signal, for each heart beat, an ST segment comprising a succession of samples of the ventricular repolarization wave, taken within a time window of a predetermined width, said width having a moment of window onset, said moment of window onset having a time offset from a predetermined temporal origin; wherein said predetermined temporal origin comprises said determined moment of appearance of the QRS complex; 
 quantizing means for computing an elevation index of said ST segment compared to a predetermined reference level; and 
 means for analyzing over a succession of heart beats, selected from the group consisting of the persistence the elevation index and the variation of the elevation index. 
 
     
     
       2. The device of  claim 1 , wherein said time offset from the predetermined temporal origin ranges from between 60 and 100 ms. 
     
     
       3. The device of  claim 1 , wherein said predetermined width of the time window ranges from between 50 and 80 ms. 
     
     
       4. The device of  claim 1 , wherein said quantizing means further comprises means for creating a matrix providing, for a series of samples (S,) taken within said time window, the amplitude (V,) of corresponding samples of the ECG signal. 
     
     
       5. The device of  claim 4 , wherein said series of samples is a subset of the samples of said succession of samples of the ventricular repolarization wave. 
     
     
       6. The device of  claim 4 , wherein said device comprises means for concurrently analyzing a plurality of ECG signals coming from different derivations, and means for applying to the matrix a mathematical transform selected from among the group consisting of:
 a principal component analysis, a KarhunenLoeve transform, and a derivative calculation. 
 
     
     
       7. The device of  claim 1 , wherein said quantizing means further comprises integrating means for computing the surface area defined by the ECG signal over the width of said time window, for determining the elevation index. 
     
     
       8. The device of  claim 1 , wherein said analyzing means comprises means for evaluating an average level of the elevation index based upon at least one of: during a given duration and over a given number of heart beats, and for analyzing the long term variations of the elevation index around this average level. 
     
     
       9. The device of  claim 8 , wherein the analyzing means comprises classifying means for distributing into a plurality of classes the successive values of said elevation index collected based upon at least a given duration and a given number of successive heart beats, said distribution into classes being operated as a function of a parameter measured by the device or known thereby. 
     
     
       10. The device of  claim 9 , further comprising means for analyzing at least one of a persistence and a variation of the elevation index, separately for each class. 
     
     
       11. The device of  claim 9 , wherein said parameter is one selected from among the group comprising of: heart rate, RR interval, diurnal nocturnal or prandial of the moment of analysis, the patient's level of activity, the patient's body temperature, the natural or paced nature of the heart beat, the sinusal or extrasystolic character of the heart beat, and the existence of a drug treatment. 
     
     
       12. The device of  claim 1 , wherein said analyzing means comprises means for searching within the ST segment, the presence of a coved pattern that is characteristic of a one of a Brugada syndrome and an Early Repolarization Syndrome. 
     
     
       13. The device of  claim 1  further comprising a graphical display of the variations over time of said elevation index. 
     
     
       14. The device of  claim 1 , wherein said analyzing means further comprises means for providing information of assisted diagnosis comprising a risk marker. 
     
     
       15. The device of  claim 14 , wherein the information comprising a risk marker is provided when the elevation index computed by the quantizing means is greater than a predefined threshold during a predetermined duration. 
     
     
       16. The device of  claim 14 , wherein the information comprising a risk marker is provided when the elevation index computed by the quantizing means is greater than a predefined threshold over a given number of heart beats. 
     
     
       17. The device of  claim 14 , wherein the information comprising a risk marker is provided when the elevation index computed by the quantizing means is greater than a predefined threshold during a predetermined duration and over a given number of heart beats. 
     
     
       18. The device of  claim 14 , wherein said analyzing means further comprises means for concurrently analyzing a plurality of ECG signals coming from more than two different precordial derivations, and wherein the information comprising a risk marker is provided when the elevation index computed by said quantizing means is greater than a predefined threshold during a predetermined duration, for ECG signals coming from at least two of said precordial derivations. 
     
     
       19. The device of  claim 14 , wherein said analyzing means further comprises means for concurrently analyzing a plurality of ECG signals coming from more than two precordial derivations, and wherein the information comprising a risk marker is provided when the elevation index computed by said quantizing means is greater than a predefined threshold over a given number of heart beats, for ECG signals coming from at least two of said precordial derivations. 
     
     
       20. The device of  claim 14 , wherein said device is able to concurrently analyze a plurality of ECG signals coming from different precordial derivations, and wherein the information comprising a risk marker is provided when the elevation index computed by said quantizing means is greater than a predefined threshold during a predetermined duration and over a given number of heart beats, for ECG signals coming from at least two of said precordial derivations. 
     
     
       21. The device of  claim 1 , wherein said device is an external recorder able to be connected to external electrodes for collecting cutaneous ECG. 
     
     
       22. The device of  claim 1 , wherein said device is an implanted device comprising electrodes for collecting a subcutaneous ECG. 
     
     
       23. The device of  claim 1 , wherein said device is an implanted device able to be connected to electrodes for collecting intracardiac or epicardiac EGM signals, said device further comprising means for reconstructing ECG signals based upon said collected EGM signals. 
     
     
       24. The device of  claim 1 , wherein said device is an implanted device of the pacemaker, defibrillator or pacemaker/defibrillator or resynchronization device, said device further comprising means for delivering pacing pulses, defibrillation shocks or both, controlled by said means for characterizing the ventricular repolarization wave.